Which of the following pairs of terms could describe a bullfrog that is active at night and enters a state of complete inactivity during cold months?
cooperation and hibernation
aggression and circadian rhythm
circadian rhythm and hibernation
courtship and cooperation

Okay, well the term: "circadian rhythm" Is A daily cycle of biological activity based on a 24-hour period and influenced by regular variations in the environment, such as the alternation of night and day.